In the transportation and construction industries, epoxy-based adhesives and foams are frequently used to provide structural support, sealing, and sound attenuation. For curing and expansion of such adhesives and foams, the addition of separate curing agents and blowing agents are typically required, adding expense and time for manufacture. Fire retardancy is also often desired, requiring additional agents for imparting the same.
Polymers having at least one epoxide group have been described in U.S. Pat. Nos. 5,115,075; 4,438,254; 6,011,111; and WO 98/14498 (see e.g., pages 3-8) along with illustrative synthesis conditions, all incorporated by reference herein (see also U.S. Pat. Nos. 3,317,471 and 4,647,648, also incorporated by reference herein). Examples of such materials also can be found, without limitation at paragraphs 15-25 of Published U.S. Patent Application No. 20070270515 (Chmielewski et al), incorporated by reference for all purposes.
U.S. Pat. No. 6,730,713 describes a material comprising an epoxy resin, phosphoric acid and a metal carbonate for forming a foam-in-place material. The use of the acid provides a desirable quick reaction for expansion and/or curing. However, the significant difference in viscosity between the phosphoric acid and the epoxy resin present significant challenges to both manufacturing and storage of the material.
The use of such polymers in a composite material has been disclosed in WIPO Patent Application WO/2008/010823 (addressing in situ reaction of an epoxy and an amine after impregnation), incorporated by reference herein. See also, United States Patent Application No. 20090298974 (incorporated by reference).
U.S. Pat. Nos. 4,992,525; 5,648,401; and 6,730,713 may also be relevant to the present teachings, and are all incorporated by reference for all purposes.
Notwithstanding the above teachings, there has remained a need for polymeric materials that are capable of foaming, curing and/or exhibiting flame retardant characteristics without the need for additional ingredients.